Impulse transmitter for automatic telephone systems



Feb. 13, 1923. 1,444,777

J. G. BLESSING IMPULSE TRANSMITTER FOR AUTOMATIC TELEPHONE SYSTEMS I Filed Jan. 26, 1920 Patented Feb. 13, 1923.

UNITED STATES PATENT OFFICE.

JOHN G. BLESSING, OF CHICAGO. ILLINOIS,-ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO. ILLINOIS, CORPORATION OF ILLINOIS.

IMPULSE TRANSMITTER FOR A Application filed January To all whom it may concern:

Be it known that I, JoHx (.ir. Buzssixo, a citizen of the I'nited States of America. and a resident of Chicago. Cook County. and

State of Illinois. have invented certain new and useful Improvements in Impulse Transmitters for Automatic Telephone Systems, of which the following is a specification.

My invention relates in general to impulse transmitters. or calling devices. for automatic telephone systems, and the object of the invention is to improve the mechanism of acertain well known type of calling device with a view to eliminating certain inherent defects having to do with the proper control of the central office switches.

Reference is made at this time to pages 3% and 35 of Automatic Telephone Practice. by Smith & ampbell. wherein is described a well known type of two wire calling device which is in common use: and also to the I. S. patent to l\'eith. #1279352. which describes an improved form of the same calling device. While my invention will no doubt be found applicable to other types of calling devices. I have developed the samein connection with a calling device of the above type and it is so shown in the present disclosure.

Such a callingdevice is adapted for use by a calling subscriber for producing successive series of current impulses in his line circuit to control the operation of a series of automatic switches at the exchange to establish a connection with a called line. These' switches have two movements. generally referred to as primary and secondary movements. and except in the case of the final switch or connector switch. the primary movement is the only one which is controlled by 40 the impulse transmitter at a calling station, the secondary movement being an automatic operation brought about. at the completion of the primary movement for the purpose of selecting the next switch in the series. \Vhile this secondary movement is quickly performed. yet it requires nevertheless an appreciable length of time for its com 'iletion. and

of course the next switch can not be operated until it is completed and the connection is extended to such switch.

It will be evident therefore that there must be a certain brief time interval between series of impulses, otherwise a series UTOMATIC TELEPHONE SYSTEMS.

26, 1920. Serial No. 354,201.

of impulses might be sent in. or started at least. betore any switch was ready to be operated. Ordinarily. a sutlicient time interval is auto-matica'lly introduced by the act of the subscriber in selecting the different digits and changing his linger from one finger hole to the next. The subscribers are also generally "instructed to remove the finger each time the dial is operated and allow the dial to come to'rest before calling the next digit. l-lowever. a subscriber will some "mes leave his finger in the finger hole at er pulling the dial around and will force the dial back. thereby causing trouble by producing too rapid a series of impulses; or perhaps he will simply follow the dial back with his hand, without forcing. it especially, butfor the purpose of immediately re-operating it. This latter occurs when the next digit to be called is the same as the one being called. there being in such instance no real necessity for removing the finger. except to secure the proper operation of the switches. and the subscriber may forget this feature. The chief object from the subscribe-rs view point is to call the digits as quickly as possible, and the recurrence of the same digit in a number presents as excellent opportunity for saving time. As a matter of fact, during busy periods when the switches have to rotate past busy trunks the faulty calling of those mnnbers which contain doubles. and especially those containing double one or double two. gives rise to considerable tro'uble.

In order to remedy the ditliculties pointed out I provide a calling device of the character mentioned with if finger stop of special construction. which is so designed that the subscriber operating the dial is compelled to remove his finger before the dial will return to normal and transmit impulses. 1 Having explained in general terms. the object of my improvement. its construction and operation will now be explained more in detail. Referring to the drawings. Fig. 1 is a front view of a calling device embody ing my invention. while Figs. 2 and 3 are rear views. the first of which shows the calling device in normal position while the second shows it in operated position and locked against return. Inasmuch as the mechanism itself iswell understood it. will not have to be described. and l will confine the description to my improvement.

To proceed. I provide a finger stop which is movable rather than fixed and which comprises a circular portion 3 and an arm 4 which is bent up and back across the face of the dial as shown in Fig. 1 so that it ma) be engaged by the finger of the operator. In order to form a bearing or pivot for the: finger stop a series of projections or studs T are formed or punched out of the frame plate 2 and are arranged in-a circle of the same diameter as the inside diameter of the ring 3. The finger stop is held in place against the frame plate :2 by means of screw 9. which passes through a slot in ring 3. and also by means of the semi-circular bridge piece or guide 8. A coil spring ll) holds the finger stop in normal position against the edge 12 of the recess cut in the periphery of the frame. while the limit of its downward movement is determined by the edge 13 of the recess. The shank of the governor carries a fixed pin 5 the end of which rotates within the plane of the ring 3. and in order to permit the free rotation of the governor the said ring has a slot 6 which allows the pin 5 to pass freely when the finger stop is in normal position.

Suppose now the dial is operated in accordance with the digit one. The linger of the operator is placed in finger bole numbered 1 in Fig. l. and the dial is pulled around. the finger carrying the linger stop with it until the said finger stop strikes the edge 13 of the recess, where further rotation is prevented. l'f now the operator permits the dial to return without removing his finger. or attempts to force it back. it will return until 'tl1 e ;finge 1- stop reaches approximatelythe position shown in Fig. 3. at which point the dog on the dial will engage the gear wheel. which will begin to rotate the pinion and governor. As soon as the governor starts to turn. the pin 5 will engage the edge of ring 3. and further rotation of the governor is prevented. Thusthe entire mechanism is locked as long as the linger stop remains in the position shown. The subscriber is therefore forced to remove his finger and release the finger stop which is at once returned to normal position by the spring ll). By this operation the slot 6 is brought into position directly below the pin thereby freeing the governor and permitting the mechanism to operate in the proper manner.

it will be seen therefore that l have devised a simple and efi'ective device rendering it necessary for the subscriber to remove his finger from the dial after calling each digit. and which effectually accomplishes the desired result. which is to prevent forcing oi" the dial and to insure an appreciable in terval between the calling of successive digits in a number.

llaving described my invention what I desire to secure and have protected by Let'- ters latent will be pointed out in the appended claims.

What I claim as my invention is:

1. The. combination. in an impulse transmitter. of a manually operable finger hole movement of Said dial. said stop being movable a definite and invariable distance. and locking means cooperating with said finger stop for preventing the return of the dial until the finger stop has first returned to normal.

3. The combination. in an impulse transmitter, of a manuallyoperable finger hole dial movable in a clockwise and counter clockwise direction. a movable linger stop for limiting the clockwise movement of said dial. and locking means preventing the counter clockwise movement of the dial while the finger stop is in an off normal position. 4. The (:ombi1'1ation. in an impulse transmitter. of a manually operable finger hole diahn movable finger stop for delaying the return movement of said dial. impulse sending mechanism operated by said dial upon its return to normal. and locking means preventing the operation of said dial and mechanism while the said finger stop is in an off normal position.

5. The combination. in an impulse transmitter, of a manually operable finger hole dial, a movable finger stop for limiting the movement of said dial. impulse sending mechanism operated by said dial upon its return to normal. and means whereby thesaid mechanism is locked against operation when said finger stop is out of normal position.

6. The combination, in an impulse transmitter, of a manually operable finger hole dial. a movable finger stop for limiting the movement of said dial. impulse sending mechanism operated by said dial upon its return to normal. and means included in said mechanisn'i. adapted to prevent its operation by engaging the said finger stop when the same is out of normal position.

7. The combination. in an impulse transmitter. of a manually operable finger hole dial. "a movable finger stop for limiting the movement of said dial. impulse sending meclnniism operated by said dial upon its return to normal, a governor for regulating the operation of said mechanism, and a pin in said governor adapted to engage the said finger stop when the same is out of normal position.

8. In a calling device for automatic telephone systems. arotatable finger hole dial having variable forward and backward movement. interrupter mechanism operated by said dial in its backward movement. a finger stop for limiting the forward move ment of said dial, said finger stop being movable a definite and invariable distance from a'normal position, and means for locking said mechanism to prevent its operation while the said finger stop is away from its normal position. i 9. In a calling device, a finger hole dial having a forward and backward movement. interrupter mechanism operated by said dial on its backward movement. a movable finger stop having normal and off-normal positions. said dial operated to set the device and to thereby move the stop off normal. and means controlled by the stop for preventing movement of the mechanism or dial while off-normal and for permitting the return movement of the dial and the operation of the mechanism when the stop reaches its normal position.

10. In a calling device, an impulse sending. mechanism. arotatable finger hole dial a movable finger stop operated in the forwardmovement of the dial. said stop preventing any movement of the finger hole dial until the stop has returned to normal.

11. In a calling device. a rotatable linger hole dial operable in a variable forward and backward movement. interrupter mechanism operable by said dial in its backward movement. a governor for regulating the speed of said dial. and a finger stop mow able a definite and invariable distance from normal position. said stop directly engage ing said governor for delaying the return movement of the dial.

12. In a calling device. a rotatable finger hole dial operable in a variable forward and backward movement. interrupter mechanism operable by said dial in its backward movement. a governor for regulating the speed of said dial. a movable finger stop r'or limiting the forward movement of said dial. and a pin on said governmfor preventing the backward movement of said dial by engaging the stop while the stop is in operated position.

Signed at (hit-ago. in the county of ook.

and State of Illinois. this 22d day of Januar v, 19:24). v

JOHN (l. BLESSING. 

